The present invention relates to lift and steering mechanisms for agricultural implements and more specifically to an assembly that can automatically adjust the height of an implement main frame and to steer implement wheels.
Large agricultural planters typically include a central frame assembly that is supported by a plurality of ground engaging wheels, one or more long tool supporting booms or wing frame assemblies mounted to the central frame assembly and extending laterally there from to, as the label implies, support planter row units, and a hitch that extends in a forward direction from the frame to link the planter to a tractor or the like for transport. A typical row unit includes a disc or other ground engaging component for opening a seed trench of a certain depth in the ground as the planter is pulled through a field, a seed dispensing subassembly for dispersing seeds in a controlled fashion into the trench and, in many cases, other components for adjusting trench depth, seed dispersal rate, etc. Here, in some cases, the total length of the main frame and wing assemblies can be ninety feet or more so that wide swaths of a field can be planted during each pass there through.
While wide planters reduce the amount of time required to plant a field, planters with large widths make it difficult if not impossible to transport the planters to and from fields to be planted. For this reason wide planters have been designed that are typically reconfigurable to facilitate transport. For instance, in many cases wide planters have been designed with extendable hitches and with the long wing frame assemblies mounted to the central frame assembly to fold forward over a portion of the extended hitch prior to transport. In these cases the ground engaging wheels on the central frame assembly continue to support the central frame and folded wing frames for transport.
While row unit trenching discs and other row unit components have to contact or be very near ground surface level during a seeding activity, during transport row units have to be raised so that they clear ground surface level. To this end many planters have been designed that include systems for adjusting the height of wing frame assemblies above ground level so that row units can be positioned at various planting heights or a relatively high transport height.
In the case of folding wing planters where a hitch extends forward and wing assemblies fold forward over the hitch for transport, while planter width may be suitable for transport, the planter length is increased appreciably, which can exacerbate the process of maneuvering the planter through turns. In this regard, when a planter hitch is extended and wing assemblies are folded into the transport position, the ground engaging wheels on the central frame assembly are far away from the end of the hitch linked to a tractor, which means that the tractor/planter assembly has an extremely large turning radius in this configuration. A large turning radius can be particularly problematic when turning off a narrow road and through a narrow pass into a field or when maneuvering through other tight spots.
Further still, large agricultural planters are typically towed by tractors that are manually controlled or steered by an operator. Planting operations for large fields may require an extensive amount of time to complete, such as several hours, and in the case of manually controlled vehicles, the operator must constantly steer the vehicle to ensure proper planting coverage. Improper planting coverage may result in lost revenues for the operator or, if additional passes are used to address unplanted areas, higher fuel costs. As a result, operators typically invest a large amount of effort to ensure all areas of a field are properly covered without requiring additional passes. However, the effort required to constantly steer a manually controlled tractor for a long period of time can easily fatigue an operator.
To address the drawbacks of manually controlled tractors, several automatically controlled tractors are presently available. Automatically controlled tractors typically include global positioning system (GPS) receivers as well as other components to automatically control the path of the tractor and the trailing planter. However, the effectiveness of automatically controlled tractors is limited because the path of the planter is indirectly controlled by the tractor. As a result, the planter may not provide proper planting coverage in some situations. For example, automatically controlled tractors may not provide proper planting coverage in strip-till operations. Strip-till operations generally involve use of a tilling implement to first provide tilled rows in a field and a planting implement to subsequently plant seeds in the field. The planting units must be appropriately positioned relative to the rows formed by the tilling implement. However, the planting units may not be appropriately positioned relative to the rows even if the tractor follows the same path for tilling and planting due to, for example, an uneven field surface.
Considering at least the above limitations of prior designs, a system is needed for directly controlling the path of an agricultural implement.